[llvm] [llvm-cov] let text mode divider honor `--show-branch-summary` `--show-region-summary` etc (PR #96016)

[Wentao Zhang via llvm-commits]

whentojump wrote:

Oh I just realized file reports and function reports are using two different `*Columns` array...

https://github.com/llvm/llvm-project/pull/96016